A conventional baler produces a bale of crop material. Moving needles wrap a tying medium, such as strands of twine or wire, around the completed bale. The needles are retracted from the bale case when a tying operation is completed after the last working stroke of the plunger which completed the bale. Each needle pivots about a fixed shaft, and is coupled to a pivoting lift arm by a lift link. Each lift link includes an adjustment linkage so that each needle can be properly positioned in the baler mechanism.
To prevent damage to the lift arms, needles and to other baler components, various types of protection mechanisms are used. Most balers have a needle protection setup which includes a bolt in shear on the lift arm that severs and a separate mechanism tied to the gearbox pushes the needles out of the chamber. Krone makes a lift link with a shearable bolt which extends transverse to the main longitudinal axis of the lift link. As a result, the force on the shear bolt is perpendicular to the axis of the bolt and the bolt has play in it. This results in higher forces to shear the bolt and fatigue loading weakens the bolt over time and causes undesired shears. The loading required to break such a shear bolt is unpredictable and can be much different based on how long the bolt has been used. Such a design may cause an undesired break of the mechanism even when there is no other failure in the baler system.